Valvular incompetence associated with venous ulceration can occur in the superficial, deep, or perforating systems. Duplex imaging was used to evaluate 95 extremities (78 patients) with current venous ulceration to determine the location of incompetence in each extremity. In addition, in 91 of the 95 extremities the area of the venous ulcer was evaluated for the presence of perforating veins or any other superficial veins or both conditions. Sixty-three (66.3%) of the 95 extremities had multisystem incompetence (superficial and perforating plus superficial and deep plus perforating and deep plus superficial and perforating and deep), whereas single system incompetence (superficial plus perforating plus deep) was seen in only 26 (27.3%). Isolated deep incompetence was identified in only two extremities (2.1%). Furthermore, 45% (41/91) of the ulcers had no duplex evidence of any venous abnormality in the ulcer bed. These data show that the site of valvular incompetence occurred in multiple locations, that isolated valvular incompetence of the deep venous system was uncommon, and that perforating veins were not always in the ulcer bed itself. Because standard venous surgery has traditionally been directed toward only one system, this may provide one explanation for ulcer recurrence. Therefore complete venous evaluation with duplex imaging allowing for surgical intervention directed specifically to the sites of involvement in each system is recommended.

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Given the relatively low stroke rate with surgery in the RCS-OP group (2.1%) and the higher incidence of unheralded strokes (7.5%) in the RCS-NO-OP group, a more aggressive approach may be warranted in patients with asymptomatic high-grade (> 75%) RCS, a strategy not unlike that adopted for primary CENDX.

This paper describes the conflict between agriculture and urban development in the Pampa Ondulada, the eco-region where the city of Buenos Aires is located and which is one of the world’s richest and most productive agricultural areas. It describes and analyzes the ecological changes brought about by urban expansion in peri-urban and rural areas between 1869 and 1991 and the form that these have taken. It also includes an analysis of the soil types where this expansion has taken place. The paper ends with a discussion of the lack of control over the continued expansion of the urban agglomeration including that caused by the closed settlements now favoured by middle and upper-income groups and the speculative parcelling of land in advance of its development.

The best way to quantitate venous reflux is still a matter of debate. Duplex-derived valve closure time (VCTs) have been used recently because they can be measured easily. We examined the relationships between VCT and duplex-obtained quantitation of venous volume and between VCT and air plethysmography (APG). Sixty-nine legs in 45 patients with varying clinical degrees of chronic venous insufficiency were studied by duplex scan and APG. VCTs were compared with duplex-derived flow calculations and with APG-derived venous filling index and residual volume fraction. The patient's mean age was 47.5 +/- 13.9 years; the mean duration of their symptoms was 13 +/- 4 years. Twenty percent had a history of deep venous thrombosis, and 29% had undergone venous surgery. No correlation was found between VCT and flow volume or between VCT and flow at peak reflux at any of the anatomic locations studied: saphenofemoral junction, greater saphenous vein, lesser saphenous vein, superficial femoral vein, profunda femoris vein, and popliteal vein. Likewise, no correlation was found between total VCT and APG-derived venous filling index or between total flow volumes and APG-derived residual volume fraction. Total VCT and total flow volumes did, however, have a moderate correlation (r = 0.65; p = 0.0003). Duplex-derived VCTs, although extremely useful in determining the presence of reflux, do not correlate with the magnitude of reflux, and should not be used to quantitate the degree of reflux.